Akari (satellite)

AKARI (ASTRO-F) was an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket into Earth Sun-synchronous orbit. After its launch it was named AKARI (明かり), which means light in Japanese. Earlier on, the project was known as IRIS (InfraRed Imaging Surveyor).

For other uses, see Akari (disambiguation).

AKARI
Artist's conception of AKARI
Mission typeInfrared telescope
OperatorJAXA
COSPAR ID2006-005A
SATCAT no.28939
Websiteglobal.jaxa.jp/projects/sat/astro_f/
Mission duration5 years, 9 months
Spacecraft properties
ManufacturerISAS
Launch mass952 kg (2,099 lb)
Dimensions5.5 m × 1.9 m × 3.2 m (18.0 ft × 6.2 ft × 10.5 ft)
Start of mission
Launch date21:28, 21 February 2006 (UTC) (2006-02-21T21:28UTC)[1]
RocketM-V, mission M-V-8
Launch siteM-V Pad, Uchinoura Space Center
End of mission
Disposaldecommissioned
Deactivated24 November 2011 (2011-11-24)
Decay date11 April 2023, 04:44 UTC
Orbital parameters
Reference systemGeocentric
RegimeSun-synchronous
Semi-major axis6,884 km (4,278 mi)[2]
Eccentricity0.0129527[2]
Perigee altitude423.9 km (263.4 mi)[2]
Apogee altitude602.3 km (374.3 mi)[2]
Inclination98.2 degrees[2]
Period94.7 minutes[2]
RAAN305.9392 degrees[2]
Argument of perigee124.2012 degrees[2]
Mean anomaly354.1441 degrees[2]
Mean motion15.1995622 rev/day[2]
Epoch9 July 2015, 13:43:21 UTC[2]
Revolution no.50455[2]
Main
TypeRitchey–Chrétien
Diameter0.67 m (2.2 ft)
Focal length4.2 m (14 ft)
Wavelengths1.7 to 180 µm (Infrared)
Instruments
FIS: Far-Infrared Surveyor
IRC: Infra-Red Camera
 

Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its 68.5 cm (27.0 in) aperture telescope.[3]

Technical design

Its designed lifespan, of far- and mid-infrared sensors, was 550 days, limited by its liquid helium coolant.[4]

Its telescope mirror was made of silicon carbide to save weight. The budget for the satellite was ¥13,4 billion (~US$110 million).[5]

History

By mid-August 2006, AKARI finished around 50 per cent of the all sky survey.[6]

By early November 2006, first (phase-1) all-sky survey finished. Second (phase-2) all-sky survey started on 10 November 2006.[7]

Due to the malfunction of sun-sensor after the launch, ejection of telescope aperture lid was delayed, resulting in the coolant lifespan estimate being shortened to about 500 days from launch. However, after JAXA estimated the remaining helium during early March 2007, observation time was extended at least until 9 September.[8]

On 11 July 2007, JAXA informed that 90 per cent of the sky was scanned twice. Also around 3,500 selected targets have been observed so far.[9]

On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far- and mid-infrared observation. More than 96 per cent of the sky was scanned and more than 5,000 pointed observations were done.[10]

British and Japanese project team members were awarded a Daiwa Adrian Prize in 2004, by the Daiwa Anglo-Japanese Foundation in recognition of their collaboration.[11]

During December 2007, JAXA performed orbit correction manoeuvres to bring AKARI back into its ideal orbit. This was necessary because the boiled off helium led to an increase in altitude. If this had continued, the energy supply would have been cut off.[12]

2008-2010

A limited observation 'warm' programme continued with just NIR.

End of mission

In May 2011, AKARI suffered a major electrical failure and the batteries could not take full charge from the solar panels. As a result, its science instruments were rendered inoperable when the satellite was in the Earth's shadow.[3] The operation of satellite was terminated officially on 24 November 2011.[13] The satellite reentered the atmosphere on 11 April 2023 at 04:44 UTC.[14]

Results

The AKARI All-Sky Survey Point Source Catalogues was released on 30 March 2010.[16][17][18]

Astronomy and Astrophysics, Vol. 514 (May 2010) was a feature issue of AKARI's results.[19]

See also

References
  1. Stephen Clark (21 February 2006). "Japanese infrared space observatory goes into orbit". Spaceflight Now. Retrieved 20 February 2010.
  2. "ATRO-F (AKARI) Satellite details 2006-005A NORAD 28939". N2YO. 6 July 2015. Retrieved 6 July 2015.
  3. "JAXA Hopes To Keep AKARI Going Despite Power Failure". Space News International. 27 May 2011. Archived from the original on 3 February 2013. Retrieved 17 August 2011.
  4. "The Infrared Astronomical Satellite AKARI and Nikon". Nikon. September 2007. Archived from the original on 2 March 2013. Retrieved 26 November 2011.
  5. "Fueling trust in rocket science". The Japan Times. 28 February 2006. Retrieved 16 May 2010.
  6. Issei Yamamura (August 2006). "AKARI Mission Lifetime". AKARI Newsletter. Vol. 16. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  7. "The Infrared Astronomical Satellite AKARI and Nikon". Nikon. September 2007. Archived from the original on 11 May 2010. Retrieved 16 May 2010.
  8. Issei Yamamura (9 March 2007). "AKARI Cryogenic Lifetime". AKARI Newsletter. Vol. 18. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  9. "Current Status of the AKARI Mission After one year of observations". Archived from the original on 31 July 2007. Retrieved 12 July 2007.
  10. Usui, Fumihiko; Kuroda, Daisuke; MÜLler, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi (2011). "Asteroid Catalog Using AKARI: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. ISSN 0004-6264.
  11. "Daiwa Adrian Prizes - Prizes for UK-Japan Scientific Collaboration" (PDF). Retrieved 20 November 2022.
  12. Issei Yamamura (26 February 2008). "Happy Birthday, AKARI!". AKARI Newsletter. Vol. 21. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  13. "赤外線天文衛星「あかり」（ASTRO-F）の運用終了について" (in Japanese). JAXA. 24 November 2011. Retrieved 24 November 2011.
  14. Joseph Remis [@jremis] (11 April 2023). "Actual decay 04h44mn 26°N 49°W" (Tweet) – via Twitter.
  15. "AKARI (ASTRO-F) Results". JAXA/ISAS/LIRA. 28 November 2008. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  16. "新世代の赤外線天体カタログ、日本から世界に公開へ" (Press release) (in Japanese). 30 March 2010. Archived from the original on 2 April 2010. Retrieved 30 March 2010.
  17. "DARTS/AKARI at ISAS/JAXA".
  18. "AKARI | Research | Archive | PSC".
  19. Bertout, C. (May 2010). "Special feature on AKARI results". Astronomy and Astrophysics. 514: E1. Bibcode:2010A&A...514E...1B. doi:10.1051/0004-6361/201014744. ISSN 0004-6361. Archived from the original on 26 February 2021.
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